Prince Cyngar was the son of King Gerren
Llyngesog of Dumnonia, born around AD 488. Scholars believe
him to be distinct from the similarly named St.
Cungarof Congresbury.

Nothing is known of his early life
but, as an mature man, he became a follower of his nephew, St.
Cybi Felyn. He accompanied Cybi on his missionary work in
Edeligion in South-East Wales and then in Ireland (possibly via Trefilan
in Ceredigion) where they settled on the Island of Aran Mor. Here, St.
Cybi bought his uncle a cow and a calf, as he could eat no solid food.
Unfortunately, once, when the calf was removed, the cow would give no milk
and Cyngar nearly died of starvation!

The household of Cybi then moved to the
Lleyn Peninsula and Cyngar lived for a while on Ynys Gyngar near Cricieth.
They finally established an important monastery at Caer-Gybi (Holyhead)
off Ynys Mon (Anglesey). From here, St. Cyngar founded the church of
Llangefni where he was probably buried.